ByMelinda Deslatte, Associated PressSeptember 4, 2012

President Barack Obama walks past debris on the sidewalks as he tours the Bridgewood neighborhood in LaPlace, La., in the Saint John the Baptist Parish, with local officials to survey the ongoing response and recovery efforts to Hurricane Isaac, Sept. 3.

BATON ROUGE, La. — At least 13,000 homes in Louisiana were damaged by Hurricane Isaac, a state emergency official said Tuesday, offering the first glimpse of the reach of the storm that struck a week ago.

A spokeswoman for the Governor's Office of Homeland Security and Emergency Preparedness said the preliminary figures were based on an initial review of communities with flooding and wind damage.

"Our preliminary assessments are driven by conditions on the ground, and in some areas flooding limits where the teams can go. We do expect that this number could rise after FEMA completes house-by-house inspections as residents register for individual assistance," said Christina Stephens.

Nearly 95,000 people signed up for individual aid from FEMA, for grants to help repair homes and replace storm-wrecked belongings, according to numbers provided by Gov. Bobby Jindal's office. The assistance for homeowners, renters and businesses was available in the 10 hardest-hit parishes.

Not all of those who register will necessarily be eligible for aid.

Isaac came ashore in Louisiana near the mouth of the Mississippi River as a Category 1 storm, relatively weak compared to other named storms that remain fresh in residents' memories. But its damage, particularly flooding, was significant in Plaquemines and St. John the Baptist parishes, inundating homes and forcing residents to seek rescue from rooftops.

Pollution problems were part of the storm's aftermath. Coast Guard Capt. Peter Gautier said authorities were dealing with about 90 pollution cases, including six active, minor oil leaks from various storage tanks and well heads. Oil that contaminated seven or eight birds in the Myrtle Grove area of Plaquemines Parish is believed to have come from tanks at what he called a defunct oil terminal damaged during the storm.

Gautier said oil leaks are to be expected in hurricanes.

"We're all very sensitive to oil spill response, especially in the wake of Deepwater Horizon," Gautier added, referring to the oil rig disaster that led to millions of gallons of oil spewing into the Gulf in 2010. "This is one that we're on top of."

Leaks and air emissions from a chemical facility at Braithwaite had been contained but railroad cars containing hazardous materials at the site needed to be righted, he said. Also, three deep-draft cargo ships ran aground during the storm, causing no pollution but requiring salvage, Gautier said.

The floodwaters were still receding Tuesday, and evacuees streamed home to assess Isaac's devastation and sweep out the muck.

Fewer than 1,600 people remained in shelters around Louisiana, according to the state Department of Children and Family Services, down from more than 6,000 at the height of the storm's flooding and rescues.

The shelter population dropped nearly in half overnight as roads cleared, more parishes allowed residents to return and the state bused evacuees home from state-run shelters in north Louisiana. The state health department reported that all evacuated nursing homes should have their residents back by Tuesday.

Meanwhile, power had returned to most parishes, as utility crews worked to repair lines harmed by trees, wind and water.

The Public Service Commission said nearly 38,000 homes and businesses remained without electricity, about 2 percent of customers, a drop from more than 900,000 outages immediately after the storm slowly wound its way through southeast Louisiana.

Schools reopened in nearly all parishes, and disaster food stamp aid was set to be available Wednesday in 10 parishes to help people buy groceries.

Even if the number of Isaac-damaged homes rises, the devastation will be nowhere near the most recent benchmark: the back-to-back blows of hurricanes Katrina and Rita, which hammered Louisiana seven years ago. The combined storms damaged more than 200,000 homes across southern parishes, according to data from the Louisiana Recovery Authority.

Coast Guard Capt. Peter Gautier said authorities were dealing with about 90 pollution cases, including six active, minor oil leaks from various storage tanks and well heads. Oil that contaminated seven or eight birds in the Myrtle Grove area of Plaquemines Parish is believed to have come from a closed oil terminal damaged during the storm.

Gautier are to be expected in hurricanes.

"We're all very sensitive to oil spill response, especially in the wake of Deepwater Horizon," Gautier added, referring to the oil rig disaster that led to millions of gallons of oil spewing into the Gulf in 2010. "This is one that we're on top of."

Leaks and air emissions from a chemical facility at Braithwaite had been contained but railroad cars containing hazardous materials at the site needed to be righted, he said.